Information storage and retrieval systems are used to store information provided by one or more host computer systems. Such information storage and retrieval systems receive requests to write information to one or more information storage devices, and requests to retrieve information from those one or more information storage devices. Upon receipt of write request, the system stores information received from a host computer in a data cache. In certain implementations, a copy of that information is also stored in a nonvolatile storage device. Upon receipt of a read request, the system recalls information from the one or more information storage devices and moves that information to the data cache.
Thus, the system is continuously moving information to and from storage devices, and to and from the data cache. One or more communication links interconnect one or more device adapters and the one or more information storage devices.
Over time, some of the information written to the one or more information storage devices is changed, i.e. updated, and revised files are separately saved. Thus, an information storage and retrieval system may, at certain times, store both historical data, i.e. superceded data, along with current data. To free up storage space in the information storage and retrieval system, the historical data may be erased.
Using prior art methods, erasing data may require a lengthy interconnect time interval for a host computer. With the need for “24×7” data processing, what is needed is a method to erase data, where that method does not tie up host computer resources.